Got a few pairs of 434Mhz transmitter/reciever (WRL-10532) . The moment receiver powered up i’m getting a barrage of bytes, has nothing to do with the data transmitted - just a non-stop stream of random data.
I’m powering it up and reading using ftdi cable - tried a couple different ones, no change.
Tried adjusting the screw - whatever that does, connecting antenna, swapping receivers - all the same.
Connecting a 10k resistor between pin 3 and ground seems to slow down the data to where the ‘bursts’ correlate to transmission intervals, but i’m still getting junk. Could it be 315MHz unit? How can one tell? Are there any other adjustments available or can i use this device with ftdi cable?
I’m not familiar with these devices but the product description and Support Tips do acknowledge these are noisy.
It’s also mentioned in some of the reviews.
Not that it helps with your situation but I’d be curious how much the noise is reduced if you were to wrap it in foil or put it into a metal box or even ground the antenna.
I’ve had good luck with the XBee 2 & 3s using 802.15.4.
Haven’t tried wrapping one in foil, grounding antenna didn’t change a thing, but looking at the signals with the scope, here is what I’ve found:
First, the data rates could not be anywhere near 4800. At that speed single 0s almost completely disappeared, as the output tends to stay ‘on’ longer then ‘off’. I settled on 600bps, though 1200 seems like worked well but i traded speed for noise immunity. Isn’t a big deal for me, i only need to transmit a couple of bytes perhaps couple times an hour.
Second, noise could be reduced by adding potentiometer between pin 3 and ground and playing with that. I got pretty clean signal between 100k and 300k. Less then a 100k the transmitted signal was degraded, more then 300k noise starting to cause problems. Probably trading between the range and noise.
Strait wire antenna works pretty well, noticeable difference in range with antenna ‘curled’ or disconnected, though i don’t have the numbers yet.
I’ve used XBees with great success in the past, but for this case i didn’t need all they have to offer, so was looking for something cheap and simple. Might turn out to be quite the opposite.
